1. Field of the Invention
This invention relates to a windshield wiper motor used for an electric windshield wiper assembly which wipes off raindrops and the like for example from windshield glass of an automobile with the wiper blade so as not disturb the driving view, and in particular to a windshield wiper motor having a breathing structure possible to breathe smoothly between the inside and outside thereof.
2. Description of Applicant's Unpublished Earlier Construction
Heretofore, there ha been such a windshield wiper motor as shown in FIGS. 6 and 7 for example.
Namely, in a windshield wiper motor 100 shown in the figures, numeral 101 is a motor part housing a rotor 102 possible to rotate in a normal and reverse direction in a motor case 103 with an opening at the end. Numeral 104 is a gear part, outside gear parts 106a and 107a of intermediate gears 106 and 107 are engaged with a worm part 102a of rotor 102 extended from said motor part 101 to the inside of a gear case 105 through a piercing hole 105a provided at an end of the gear case 105, and an output gear wheel 108 is engaged with pinion parts 106b and 107b of said intermediate gears 106 and 107, an output shaft 109 fixed to the output gear wheel 108 is made into an output and extending to the outside of the gear case 105.
The motor part 101 and the gear part 104 are connected at respective ends of the motor case 103 and the gear case 105, and a through hole 105b communicating with the inside of the gear case 105 and the inside of the motor part 101 at the end of the gear case 105 on the motor part 101 side makes the gear part 104 and the motor part 101 into the communicating state as shown in FIG. 7.
Numeral 110 is a breather, disposed in an air hole 105d pierced through in a part of a bottom plate 105c of the gear case 105 and connecting the upper and lower sides of the bottom plate 105c in FIG. 6, in the downwardly pressed state as shown in FIG. 6. The breather 110 is provided with a shell shaped part 110a at the lower side thereof in FIG. 6, a breather hole 111 is formed which communicates crookedly with the inside and the outside of the gear case 105 through the shell shaped part 110a. So that, the penetration of water or the like into the inside of the gear case 105 or motor case 103 owing to the breathing action caused by generation of heat accompanying the working and stopping of the windshield wiper motor is prevented.
However, in the windshield wiper motor 100 as described above, for example on occasion of air inhalation in the breathing action caused by heat generation, lubricating oil applied on gears in the gear case 105 sometimes penetrates into the through hole 105b provided in the gear case 105. There is a problem that the breathing action becomes impossible in the case the through hole 105b is closed with said lubricating oil. Also in the breather 110 provided in the bottom plate 105c of the gear case 105, lubricating oil applied on gears in the gear case 105 sometimes penetrates into the breather hole 111, there is a problem that the breathing action becomes impossible similar to the case of through hole 105b.